Without opening a can of worms (aka brand specific)
-One you can afford
-Preferably a V-Drive
-One with decent freeboard to allow for listing
-One with a good amount of storage to put ballast, preferably one that has internal ballast so you don't have as many sacks

Old thread but on a budget a Tige 24V is probably the best bang for the buck. I would put it up against my Z3 any day of the week. It makes a monster swell and very easy to weight with out any bags in the way. Get the 6.0L if you can. It just sips gas 10+ hrs to a 48g tank. This is surfing and boarding.